“Read it Later” Apps

For a side project I’m working on, I want to support several different “read it later” type applications. Looking for apps that have both mobile support and APIs, it looks like the most popular options are Instapaper, Read It Later, and Readability.

All of these accomplish a similar task: bookmark a web page for later reading, and formatting it for easier reading. Mobile support is usually included, either for reading articles bookmarked earlier, or marking new ones to read on a desktop at a later time.